1. Fields of the Invention
The present invention relates generally to weighing crop bales on an electronic scale in a mobile crop baler, and more particularly, to an electronic scale in which the bale-receiving-structure is pivotably connected to load cells fixed to the baler to prevent damage to the scale during use. The scale weighs bales more accurately and can be retrofitted to existing balers.
2. Discussion of Background and Prior Art
Apparatus and methods for mechanically or electrically weighing crop bales are well known.
A standard bale chute and weight indicator is a mechanical scale for weighing bales and displaying the bale weight on a mechanical indicator. It is designed for use with a standard mobile baler such as the Freeman 370. In such a combination, the Freeman 370 discharges the bale from the rear of the baler onto a platform pivotably connected to the baler. The weight of the bale pulls down on a resilient bale chute spring-chain which rotates a lever around a shock absorber pivot to indicate a bale weight. After the bale is weighed, a pyramidal bale turner "kicks" the bale to a discharge position in the bale chute by imparting a counterclockwise quarter turn, standing the bale upright in the field as the bale is discharged from the platform. The problem with these typical methods and apparatuses for weighing bales is that they are crude and unable to consistently weigh bales accurately.
Kruger U.S. Pat. No. 2,982,201 ("Kruger") disclosed another apparatus for mechanically weighing bales, like the one used with a Freeman 370, and also using a mechanical weight indicator. Kruger's bale chute platform is hinged directly to the baler, as in the Freeman 370. Kruger requires the operator to manually adjust the bale pressure density so that the actual bale weight is maintained at a desired level.
Schrag, et al. U.S. Pat. No. 4,742,880 ("Schrag") disclosed a method for electrically weighing and displaying the weight of the bales on a platform which is a separate accumulating cart coupled to the baler and wherein the bale pressure density is manually adjusted to maintain actual bale weight at a desired level. In this structure the load cells are fixedly connected to the cart's platform. The problem with this method is the investment in an expensive cart in addition to the baler in order to weight the bales produced by the baler and the absence of an automatic feedback controller. The Ford New Holland 2000 baler is like Schrag with the additional feature of reading out and automatically adjusting bale pressure density to automatically maintain bale density at a predetermined level.
One of the inherent problems of weighing bales by maintaining predetermined density is that the internal density of the bale is highly variable and non-uniform throughout the bale. Therefore, depending on where the bale sits on the platform and where its center of gravity is located, the scale reading of the bale weight is highly variable and inaccurate. Typically, prior art scales weigh bales only within a 20 pound accuracy.
In overcoming the problems and limitations of the prior art, it is an object of the present invention to weigh bales in an electronic scale directly attached to the bale chute the platform of which pivots to prevent damage to the scale (i.e. baler going over berms in the field).
It is another object of the present invention to provide an electronic scale that weighs bales to within a 2 pound accuracy when the baler is moving and to within a 1 pound accuracy when the baler is stationary.
It is a further object of the present invention to provide a scale that has the capability of being retrofitted to presently existing balers.